1. Field
The present invention relates to fuel regulators and more particularly to fuel regulators for use with charge forming apparatus in which excess fuel is recirculated.
2. Prior art
The prior art includes various examples of fuel injection and pressure carburetion in which fuel is supplied under pressure and excess fuel is returned. Devices can be employed for modifying the upstream or downstream pressure or both in accordance with a parameter indicative of fuel requirement such as manifold vacuum.
The prior art also includes charge forming apparatus as shown in U.S. Pat. No. 3,785,627 of a type in which excess fuel is returned and in which fuel is metered by means of the impact of the air stream on an open fuel channel. In U.S. Pat. No. 3,785,627, it is taught that the air-fuel ratio characteristic can be changed by changing the shape and/or size of the opening in the fuel channel. Plural fuel channel openings may be employed in order to achieve a desired air-fuel ratio over an extended range of engine operation. Changing the air-fuel ratio of such apparatus, employing plural channel openings, requires considerable care in adjusting the size or shape of one or more of the channel openings to achieve the desired result.